The report released today by the USDA Office of Inspector General (OIG) reveals serious flaws in the USDA mad cow surveillance program. As a result of our review of this report, we believe the USDA surveillance program is spending much of its resources looking in the wrong places for this disease. USDA has not adequately sampled the cow populations that are at highest risk for bovine spongiform encephalopathy (BSE), also known as mad cow disease.
The USDA surveillance program has identified two positive cases of BSE in the United States. However it sampled less than one percent of the total US cattle population last year. USDA was supposed to test the highest risk animals. However it is plain from the OIG report that many animals tested were not those at highest risk. Thus the program may be missing significant numbers of additional cases of BSE that could exist in the United States.
The following are the categories of cattle that are at highest risk for BSE, along with the OIG’s findings on whether the USDA’s testing program is reaching them.Older Cattle: The ages of the cattle tested by USDA are not known to the public. It is thus impossible to tell whether the surveillance program is getting valid results. A cow’s chances of showing signs of BSE increase with age. The two positive cows identified in the USDA program so far were seven and twelve years old respectively. The disease is seldom detected in cattle under the age of two years. It is thus extremely important to know whether USDA has been testing older cattle, especially animals seven years old and up. Neither USDA nor the OIG report state how many of the 356,195 cattle USDA tested from June 1, 2004 through May, 2005 were in this age group. Nor do we know how many were under two years old, a group in which we would expect to find almost no positive results.High Risk Geographical Regions: The two cases identified in the US so far were from Texas, and Washington State. The latter was born in Canada, and five cases have been found in Alberta. It would thus make sense for the USDA to take extra samples from the states bordering Canada and in Texas. USDA did not take extra samples however in the Pacific Northwest or in Texas. In fact, the sampling rate in the Pacific Northwest, 76% of USDA’s goal for the region, was the lowest of the 6 regions in the U.S.Animals Showing Signs of Disease: USDA had said it would test cattle that showed signs of central nervous system (CNS) disease. However it appears to have tested very few such animals. According to the OIG report, one problem is that slaughter facilities routinely pre-screen and reject incoming animals that show CNS symptoms before a USDA inspector sees them. The inspector therefore fails to select such animals for testing. Instead, 87 percent of the cattle USDA tested were dead on arrival at a rendering facility, cause of death unknown. Cattle die and get sent to the renderer for many reasons, including heat, various diseases, and birthing difficulties. While dead animals are higher risk of BSE than living healthy animals, many dead animals are not high risk. Especially given the lack of information about the age of the animals tested, it is hard to judge how many of the animals USDA tested really were high risk.
Because of the many shortcomings of the USDA testing program, it is possible that USDA is missing BSE cases in the United States. Consumers Union urges USDA to correct the shortcomings identified by the OIG and to continue the surveillance program at an expanded level next year.